This proposal has been conceived as an in-depth study of short-term and long-term behavioral correlates of intrapartum fetal heart rate (FHR) patterns among humans. It is only within the past two decades that a fairly comprehensive knowledge of fetal autonomic responses to labor has been developed, and most of this information is related to periodic increases or decreases in FHR that accompany uterine contractions. Despite the well documented effects uterine contractions can have upon fetal physiology, including the effects of oxygen deprivation on FHR patterns themselves, there is an embarrassing lack of systematic follow- up of infants who exhibit ominous patterns (i.e., decelerations), and even less information relating genetic/constitutional factors to response typologies. To address this issue, three interrelated studies of FHR patterns will be conducted. The studies will address 1) statistical/parametric properties of FHR patterns and uterine contraction activity, 2) short-term (1 year) behavioral and temperamental correlates, 3) long-term (13-15 years) cognitive and behavioral correlates among high and low risk subjects. The proposed studies represent a systematic examination of a phenomenon known to be a potent perinatal determinant of mortality and morbidity. Moreover the combination of short-term and long-term follow-up is unique among behavioral studies, and promises to help clarify the significance of fetal responses for behavioral development. This research should also shed light on the vexing problems of obstetric malpractice litigation by addressing the role of benign vs ominous FHR as a precursor of non- optimal behavioral development.